Color analyzing device



Sept. 12, 1944. l G. EL MiLLER 2,353,020

COLOR ANALYZING DEVICE Filed Aug. 31, 1940 2 sheets-sheet 1 ATTORNEYS Sept 12 1944# G. E. MILLER f 2,358,020

i I COLOR ANALYZING DEVICE I 'Filed Aug. 3l, 1940 A 2 Sheets-Sheet 2 Patented Sept. 1944' zisaozc County, Ohio, -a'ssignor-tovGenera;l. Motors'Gor-v .poration, ADayton', i()liiog a.v corporation o'flela- Waffe comms.'

'This `invention relates to means for .analyzingl the lcolor of the finish Ion' refrigerator cabinets and other surfaces.

When .refrigerator cabinets are coated With- 'porcelain .or other materials, 'the nshed 'parts are not always exactly the same shade. This is also` true with respect to many Vother products.. Heretofore, :surfaces have .mainly been matched and graded byeye. Insome cases special meteringv systems have been used but special handling wasr required' under. this arrangement.y

Application. August, T940, SeriaINo: 35.5.,'0155 Ylteferrlingnowto the-.drawings andf` moreypar'- ticu'larly rtorigf. 1 .there isl shown a' conveyor 220@ `of yan. assembly line: hayinggrefrigerator vcabinetsV l 2525, Azit-fami: 162 being conveyed lthereon.. Sin:

It is an object -of my invention to provide av color analyzing device suitable `for grading re'- frigeratorl cabinets and l:parts Ethereof while onV f the assembly line'. f

It is another' object of my invention to provide a portable color` analyzing device which can :be

held in one Ahand and applied ,toi a. moving or stationary vsurface iny substantially any desired position.

.It-is another object. ofmy invention to provide aV color analyzing ldevice employing oniyindireet or diffused :light 'for grading purposes.

.It is'. another .objectof'myinventionto provide' a color analyzing device which.willberespon'sive to. lan illuminated' area: 'as distinguished fromV direct reflected light; A i

Further objects and advantages of thepresent' invention will .be apparent from. the following description, reference beinghad. tothe accompanyingl drawings wherein-apreferred lformY of: the present inventioni'sucleariy shown'.

In the drawings:

Fig., 1f isfa `perspective view fofone form of my invention illustratingfits application 'to ref-rigerator cabinets moy-ing. upon the conveyor ofian:

ordinary assembly line;

Fig. 2 is afront view-of the-scanning. unit;1 :and Fig. v3 is a `vertical.*sectionzaliview ofthe-scanning unit.. Y

Briefly, lha-ve shown a co'lor'zanalyz'ingv device; including a .portable scanning unit ad'apted-.tobe held .-in:1.one=hand fand appliedddirectly tofvariousr surfaces of,` objects .moving iupon: a. conveyor. :or -dsposed 'in any manner. Thezscanning unit in4 cludes a light. source, 'a light. sensitive element.

and a. shield' for' excluding external light and' for confiningl the vlighty Yproduced by' the; light source.

The 'light sensitive yelement controls the; flow of minute `electric `current'.which' is ampli-- Y fledy inv a separate much lessxportabley unitv Whichi in turn supplies the .amplied current Vto` -ae m icroammeter whicn= -`i'neasuresy the current. 'to` indications provided yby theA micro-ammeter'inA dieet-ing various .-shadesrof color..

.speci-or` Ruis tshownl applying 'th'e novel'- portable.

scanning uniti frito-:a `portion o'fxth'e refrigerator cabinet -2`41as1i't `passes-Toy.1on1 tlie conveyor. `scanning -unit 530? may' he'. eitherv held.. 2in ones-spot vuponthe cabinet crit may be? moved across?. the:

'various surfaces 1in. vorderl to obtain af. ybetter average colorxindication.. The sscanningunitincludes :a source Yof lightganda flight. sensitive element'. A .shield .fisgprovid'ed for -connnin'g :thee

.light fto `the Iportion oftheecabinet 'surfaceadan jacent .the lightsensitivey element. slieldf also-servesuto excludeextraneousilight. K

The scanning unit 301` connected`v `by rade'-l quately shielded iieX-i'ble electrical' conductor Iupon'. -the---iloorin onev positibnriatcall timesv.. This cabinet.53'4 includes an 'amplifying'iportioniior amplifying the current controlled `by the" light' sensitive elementloffthe scanning: 'Therebinet also. includes faz. iba'i-.tery' portion il :and:t a

voltage regulating. Portiony 'lili for i supplying.elec4 tric energy-:alt 'an extremely uniformy voi-tage. Sto;

.tnelightmsourcezand fthe lig-ht. sensitive. element? vEither a fdirectl @or alternating current supply'.

source .may `bey used. The current; amplified in the amplifying portion= 361 .is conductedb the conductor .'42lk .to' the micro-ammetei;

miero-ammeteri A'Ifmayf be.imborlmray cabinet 3l or:it.may-'rinesplaceri-` zat'any sul lef of the cabinets; Or-.dinan inthe-.inspector 1li-wmt ystamp=upon.tirefcabinuairttiereamnn ofl'themicroi u The 4'cabinet 3"5- rvis fprovitiedywith: a combined -`microaanmeter :and: yol'tmeter 'seyera'l suitablevscal'es.. Aselector'switch vis'.proyirled )to .selectively vsupplyr the. controlled.; the 'light 'sensitiyeielement and amplified amplifying. portion; 561' to re'itlrnfrf' indicating-L meter Y#iffor;.the1'com-bined:meter :l cribothf.y

secondV .selector switch. is: provided. for. connecting? the'combined-meter lil` to variouseparts. of the amplifying: portion '3.6.1 :as wellv sas.y the bat-I teryv portion 38 the voltage regulating 'por-V tion 41D; indicating-flight .illi isz provided yfor Iindica-tingr when. theVoltagel lis von. Anz."iritiicait-` ing light ilLl19`fis-fprovidedifor indicating when vthev .meter 'Il y provided with( ra" c'alibriaf-tiifig lr-nolil illl.k

When- 'usingqtheffapparatua' one: cri more:sam-` inuoperation.. The 'cabinetflfiaalso pleV panels of known color analysis are used as a standard. These may be fastened to one of the walls of the cabinet 84. The scanningunit l0 is applied to one oi' the samples and the calibrating knob is adjusted to bring the hand of the indicating meter to the correct color value of the sample.l Other samples of other shades may be used to check the adjustment. In selecting a door' for the cabinet this reading is noted and a door having a similar reading is selected and attached in its proper place in the cabinet. Thus,

by this method of selection the door will match within very close limits the remainder of the cabinet.l v

As shown in Figs. 2 and 3,`; the scanner '28. in# cludes a housing or cylindrical shield" having a handle unit l2 connected toone end of the shield 50.- 'I'his handle unitcontains a socket M which receives a current-passing type of pho-` toelectric cell 58. For grading porcelain, the socalled blue sensitivephotoelectric cell 'is' prefer'x'ed.` That is, this cellfisdesigned to have a color'sen'sitivity which' reaches `a maximum in theI blue region lof the spectrum.y This cell is", sonetimescalled a rubidiumphototube, since it has adheavy rubidium `coating upon the cathodewhich is preferably semi-cylindrical.- The photos0 as t'ofprcufideV somey ventilation'around the photocell -58 y"to prevent it from'` overheating.

Fastened by the bracketsv to theV casing 50 vare three automobile typelampbulb sockets 88 which are distributed 120 apart. Each of these bulb sockets I8 is provided with a'single'illament vautomobile headlight bulb "of a normal' rating ofe'ither Vdor 12 volts'. Each of the Alight bulbsVv is'p'rovlded `with areflector 1I for directing light costs are higher, polishing is more dilcult and the weight is greater.

n This member 8,I| is in the shape of a truncated cone andY has a polishedlarge end surface 82.

This polished surface is perfectly plane. The round portions of the member 88 are roughened and may be coated with paint so as to prevent reflection within the member 88. The opposite rayst emitted-by" theffllament onto the surface tobe analyzed;4 The front edge of the 'cylindrical' shield or housing" 58 isgprovided with a removable rim 12 which'is provided with some for'rnoffexV tremelyfelrible fr'u'b'berseal for the purpose of" making sealingcont'act with the suiiiiice to be analyzed ,regardless of its conguration. shownjthe rim 'l2 is provided' with a ring 1l of sponge rubber or some other suitable *materiall 1 inorder to providea vsealing light l'excluding contact with the surface to bje" analyzed. A'I'l'ie sur-fv face to, begannen-is indicated in dot lines by the reference 'character 18. v 'As an important"featureV of my invention I anclY 'dash provide iinji1`nproved-andl novel means forvsecur-1 ingjbtte"gradingl Vresults by only transmitting the light emitted substantially normal tothe facet be analyzed-B'y this improved means, I

alsoA prevent the transmission of thedi'rec't reflec? tional of the f lightfeniittedy byV the light source: that is; thegli'ght bulbs 88. For this purpose I provide a lsolid member 8l. Preferably this memberfvlfis almaterialknown best by several of its tradenanies, such as' Lucite," Crystall'te" andv Plexiglas This material is a polymethyl .niethacrylate 'andl has the poly formula- 'I'his materialris preferred since ittakes a very" high polish and .therefore `can-provide high reecting power solthat 1 onlylightf rays entering As Y isis rather than direct reflected light from thelight bulb 68.v vThis is ybecause the surface 82 isperfectly planeV and highly polishedl and will admit only light projected substantiallynormal to itsg The member 80 is supported by three removable clips 86 whlchare fastened to the vvertical wall 88 `which supports the reflectors 10. The distance maintained between the polished face 82 :of the member- 8U and the surface Vof the workbeing j -analyzed is highly important, since,if the work is too far away from the surface light willbe reflected substantially normal to the surface and will be admitted by the member 80. If the sur.-

face `to be analyzed is placed too close to thel pol.V ished surface 82 then the surface to be analyzed will not have uniform illumination. Ihave found that the proportions shown in Figs. 2 and 3 provide substantially uniform illumination and yet j prevent direct reflected light from being admitted -byvthe member 80 and'transmitted to the photo- Y The unit 30 is provided with arhook 90. The handle 52 is made hollow for receiving vthe shielded flexible conductor 32 which contains conductors connecting to the socket 5l aswell as to each of the sockets 68.' Thevoltage regulator I0 provides an accurately regulated supply of electrical energy to each of thefbulbs so that a very uniform source of light is always provided. This scanning unit 30 is iilleil` with a light weight .insulating material 82 and is relatively smalll and light in weight and can readily-be applied'to the cabinets as they pass by upon the conveyor 20. All the metal Partsare. painted with a flat tone or dull black paint to prevent reflection.

Only the necessary elements are placedin the scanning-unit 8l so thatv it will'bekept aslight and portable as 4possible and the remaining units are located in thefrelativelystationary cabinet Il. with the exception "of the: micro-ammeter 'u which may belocated where it is most convenient to'read. z l Y The micro-ammeter is preferably of thesuppressed type. That is, the meter is of such a type `that theflrstportion of the scale is suppressed'A in order to spread usable portions ofthe scaleV to obtaina wider deflection of the meter and for the same change in meter.

While the form or embodiment of the inventhe polished surface will current passing through the l tion as herein disclosed, constitutes a preferred might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A color analyzing device for surfaces to be analyzed includingv a light sensitive element, a solid light transmitting member located adjacent said light sensitive element for transmitting light thereto, said member having a plane polished light entering surface for reducing the amount of light rays admitted at a substantial angle to its surface, spacingineans for holding.

the entering surface in spaced generally parallel relationshinwith respect to the surface to be analyzed, and a light source located laterally of the polished light entering surface for illuminating the surface to be analyzed and materially reducing the amount of directly reflected light entering the member, and supporting means for said element, said member and said light source.

2. A color analyzing device for surfaces to be analyzed including a light sensitive element, a solid light transmitting member having a light exit surface located adjacent said light sensitive element for transmitting light thereto, said member having a plane polished light entering sur-v face for reducing the amount of light rays admitted at a substantial' angle to its surface, aA

plurality of sources of light equally distributed around the light entering surface so that direct reflections of the light from the surface to be analyzed will strike the polished light entering surface at a suflicient angle to materially reduce the proportion of direct reflected rays entering the light entering surface, and supporting means for said element, said member, and said lightl source.

3. A color analyzing device for surfaces to be analyzed including a light sensitive element, a solid light transmitting element having a light exit surface located adjacent the .light sensitive elementy and a plane polished light entering surface, a light source surrounding the light transmitting element for illuminating the surface to be analyzed, said light source being located substantally in the plane of said plane polished surface, means Yfor shielding the transmitting element and the sensitive element from the direct rays cf the light source, and supporting means fcr said light sensitive element, said light transmitting element, said light source and said shielding means.

4. The method of color determination which includes illuminating the object the color of which is to be determined, placing a substantially plane polished light-entering surface of a light transmitting member near said object and disposed laterally of the source of illumination at an acute angle tol thepath of'specularly reflected light whereby the greater portion of the specularly reflected rays of light reaching the polished surface is reflected from the polished surface and the greater portion of the light admitted by the transmitting member is diffused reflected light,

and measuring the light transmitted by the lightV transmitting member.

GEORGE E. MJLLER. 

